Well functioning timing chain drives are required especially in the field of internal combustion engines. In this connection there are great requirements as to the low noise level of such chain drives, so that numerous measures are undertaken so as to avoid unnecessary vibrations and running noises caused by the same. It is generally known that a steadier movement can be expected if the chain wheels have a larger number of teeth, which is the reason why the reluctance to use smaller chain wheel sizes is high. On the other hand, the ambitions to provide more compact internal combustion engines and chain drives required therefor are increasing. With a camshaft/camshaft drive for a motor vehicle engine alone the axial distance between both camshafts sets limits, which have to be considered.
One possibility to reduce the axial distance between both camshafts is described in DE 10019458. With this construction, a duplex chain is applied into which two camshaft chain wheels arranged to be offset to each other engage. The empty track laterally positioned next to the respective chain wheel is then supported by specifically formed sliding rails.
Other chain drives overlapping or covering each other are known from U.S. Pat. No. 5,471,895, DE 3347638 C2, WO 83/02307 A1, EP 0575044 A1, JP 60-91054 and JP 57-210109.
Moreover, one chain drive is described in DE 10042041, which has support wheels arranged laterally next to the associated chain wheels. With the use of a duplex chain these support wheels support the marginal region formed by the outer plates. The circumferential surface of the support wheel therefore corresponds to the contour defined by the adjacent outer plates. With these constructions axial distance reductions may be performed, which are partially considerable. However, with a movement of the multiple chain, which should be as steady as possible, also the wear properties of the drive should be improved.